Soil Nutrient Release From Zaozhadian Wetland And Phytoremediation In Wetland Ecological Restoration

Baiyangdian is the landmark of Xiong’an New Zone and the living resources of local residents.Zaozhadian is the entrance wetland of Baiyangdian,and the strength of the wetland ecological function determines the quality of wetland water and its ecological function.The Zaozhadian is seriously soiled and fragmented.As the water project progresses,Zaozhadian will gradually become a near-natural wetland.In this study,the evaluation of Zaozhadian soil and soil nutrition release were carried out,to clarify soil base pollution in the region and the impact of soil nutrient release on overlying water bodies.,Water purification of phytoremediation with warm-season and cold-season wetland plants was conducted to clarify the effectiveness of warm-season and cold-season plant configuration on the ecological restoration and water purification of Zaozhadian.The study provides experimental basis for the ecological environment governance of Zaozhadian wetland.(1)The soil evaluation and nutrient release experiments of the Zaozhadian area found that the soil was mostly of medium and rich nutritional levels.The soil total nitrogen content range was 0.9-1.5 g/kg,and the soil total phosphorus content range was 0.7-1.4 g/kg.Soil with long-term cultivation and around the villages and towns had higher levels of total nitrogen and phosphorus.When the Class III water(Surface water quality standard)was used as overlying water for the release experiment,the release of soil TN and TP could pollute the water quality to Class V.The Class II water(TN is in Class III)(regarded as low-concentration overlying water),the Fu River water and the Class III water(TN of Class V)and Class IV water(TN exceeding Class V)(regarded as high-concentration overlying water)were used for different release experiments.With the low-concentration overlying water,the nitrogen and phosphorus were released to a greater extent,the release was fast,and the release of TN and TP could pollute the water quality to Class IV water.With the Fu River water and high-concentration water as overlying water,only the pollution risk of TP was large,and the pollution duration was long.(2)Cannabis,Ceratophyllum spicatum,Myriophyllum spicatum and their mixed configuration were used as the experimental plants in warm season,and Fu River water and Class IV water and Class V water were used as the influent.With the Fu River water and Class IV water as influent,the plants had a good effectiveness of water purification and inhibiting the release of TP and ammonium nitrogen,and the purification and release inhibition of TN and nitrate nitrogen were relatively small.The risks of TN,TP and nitrate nitrogen were large,and the release was large and rapid.With the Class V water as influent,total nitrogen and phosphorus were still released,which reduced the water quality and undermined the plant purification effect.Compared with single wetland plant,the mixed plant configuration had a better effect in inhibiting nutrient release and purifying water quality.(3)Potamogeton crispus as an experimental plant of cold-season wetland plants had a 50.2% reduction in the release of nitrogen and phosphorus,and obviously weakened the release of TN,TP and ammonium nitrogen.But the release of TN and TP still had the risk of deteriorating water quality to the next Class.Potamogeton crispus for Fu River water and Class IV water had an average purification efficiency of TN and TP of 47.2% and 40.3%,respectively,and for Class V water had 21.6% and 32.7%,respectively.The purification efficiency of ammonium nitrogen and nitrate nitrogen was 78.4% and 36.2%,respectively.Potamogeton crispus had a good effect in reducing the release of soil nutrients and purification of water pollution during the restoration of Zaozhadian wetland.